<title>高精度减法</title><link href="http://hzoi.com/tomorrow.css" rel="stylesheet"><div class="ui existing segment"><pre><code><span class="pl-cp">#include</span><span class="pl-cpf">&lt;cstdio&gt;</span><span class="pl-cp"></span>
<span class="pl-cp">#include</span><span class="pl-cpf">&lt;cstring&gt;</span><span class="pl-cp"></span>
<span class="pl-cp">#include</span><span class="pl-cpf">&lt;iostream&gt;</span><span class="pl-cp"></span>
<span class="pl-k">using</span> <span class="pl-k">namespace</span> <span class="pl-n">std</span><span class="pl-p">;</span>
<span class="pl-k">const</span> <span class="pl-kt">int</span> <span class="pl-n">MAXN</span><span class="pl-o">=</span><span class="pl-mi">250</span><span class="pl-p">;</span>
<span class="pl-kt">int</span> <span class="pl-nf">main</span><span class="pl-p">(){</span>
        <span class="pl-kt">char</span> <span class="pl-n">a</span><span class="pl-p">[</span><span class="pl-n">MAXN</span><span class="pl-p">]</span><span class="pl-o">=</span><span class="pl-p">{</span><span class="pl-mi">0</span><span class="pl-p">},</span><span class="pl-n">b</span><span class="pl-p">[</span><span class="pl-n">MAXN</span><span class="pl-p">]</span><span class="pl-o">=</span><span class="pl-p">{</span><span class="pl-mi">0</span><span class="pl-p">},</span><span class="pl-n">d</span><span class="pl-p">[</span><span class="pl-n">MAXN</span><span class="pl-p">]</span><span class="pl-o">=</span><span class="pl-p">{</span><span class="pl-mi">0</span><span class="pl-p">};</span>
        <span class="pl-kt">int</span> <span class="pl-n">da</span><span class="pl-p">[</span><span class="pl-n">MAXN</span><span class="pl-p">]</span><span class="pl-o">=</span><span class="pl-p">{</span><span class="pl-mi">0</span><span class="pl-p">},</span><span class="pl-n">db</span><span class="pl-p">[</span><span class="pl-n">MAXN</span><span class="pl-p">]</span><span class="pl-o">=</span><span class="pl-p">{</span><span class="pl-mi">0</span><span class="pl-p">},</span><span class="pl-n">dc</span><span class="pl-p">[</span><span class="pl-n">MAXN</span><span class="pl-p">]</span><span class="pl-o">=</span><span class="pl-p">{</span><span class="pl-mi">0</span><span class="pl-p">};</span>
        <span class="pl-n">scanf</span><span class="pl-p">(</span><span class="pl-s">&quot;%s%s&quot;</span><span class="pl-p">,</span><span class="pl-n">a</span><span class="pl-p">,</span><span class="pl-n">b</span><span class="pl-p">);</span>
        <span class="pl-kt">int</span> <span class="pl-n">s1</span><span class="pl-o">=</span><span class="pl-n">strlen</span><span class="pl-p">(</span><span class="pl-n">a</span><span class="pl-p">),</span><span class="pl-n">s2</span><span class="pl-o">=</span><span class="pl-n">strlen</span><span class="pl-p">(</span><span class="pl-n">b</span><span class="pl-p">),</span><span class="pl-n">s</span><span class="pl-o">=</span><span class="pl-n">max</span><span class="pl-p">(</span><span class="pl-n">s1</span><span class="pl-p">,</span><span class="pl-n">s2</span><span class="pl-p">);</span>
        <span class="pl-kt">bool</span> <span class="pl-n">fu</span><span class="pl-o">=</span><span class="pl-nb">false</span><span class="pl-p">;</span>
        <span class="pl-k">if</span><span class="pl-p">((</span><span class="pl-n">s1</span><span class="pl-o">&lt;</span><span class="pl-n">s2</span> <span class="pl-o">||</span> <span class="pl-n">strcmp</span><span class="pl-p">(</span><span class="pl-n">a</span><span class="pl-p">,</span><span class="pl-n">b</span><span class="pl-p">)</span><span class="pl-o">&lt;</span><span class="pl-mi">0</span><span class="pl-p">)</span> <span class="pl-o">&amp;&amp;</span> <span class="pl-o">!</span><span class="pl-p">(</span><span class="pl-n">s1</span><span class="pl-o">&gt;</span><span class="pl-n">s2</span><span class="pl-p">)){</span>
                <span class="pl-n">strcpy</span><span class="pl-p">(</span><span class="pl-n">d</span><span class="pl-p">,</span><span class="pl-n">a</span><span class="pl-p">);</span>
                <span class="pl-n">strcpy</span><span class="pl-p">(</span><span class="pl-n">a</span><span class="pl-p">,</span><span class="pl-n">b</span><span class="pl-p">);</span>
                <span class="pl-n">strcpy</span><span class="pl-p">(</span><span class="pl-n">b</span><span class="pl-p">,</span><span class="pl-n">d</span><span class="pl-p">);</span>
                <span class="pl-n">fu</span><span class="pl-o">=</span><span class="pl-nb">true</span><span class="pl-p">;</span>
        <span class="pl-p">}</span>
        <span class="pl-n">s1</span><span class="pl-o">=</span><span class="pl-n">strlen</span><span class="pl-p">(</span><span class="pl-n">a</span><span class="pl-p">);</span>
        <span class="pl-n">s2</span><span class="pl-o">=</span><span class="pl-n">strlen</span><span class="pl-p">(</span><span class="pl-n">b</span><span class="pl-p">);</span>
        <span class="pl-kt">int</span> <span class="pl-n">j</span><span class="pl-o">=</span><span class="pl-n">s1</span><span class="pl-p">;</span> 
        <span class="pl-k">for</span><span class="pl-p">(</span><span class="pl-kt">int</span> <span class="pl-n">i</span><span class="pl-o">=</span><span class="pl-n">s</span><span class="pl-p">;</span><span class="pl-n">j</span><span class="pl-o">&gt;=</span><span class="pl-mi">0</span><span class="pl-p">;</span><span class="pl-n">i</span><span class="pl-o">--</span><span class="pl-p">){</span>
                <span class="pl-n">da</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">]</span><span class="pl-o">=</span><span class="pl-n">a</span><span class="pl-p">[</span><span class="pl-n">j</span><span class="pl-o">--</span><span class="pl-p">]</span><span class="pl-o">-</span><span class="pl-sc">&#39;0&#39;</span><span class="pl-p">;</span>
        <span class="pl-p">}</span>
        <span class="pl-n">j</span><span class="pl-o">=</span><span class="pl-n">s2</span><span class="pl-p">;</span>
        <span class="pl-k">for</span><span class="pl-p">(</span><span class="pl-kt">int</span> <span class="pl-n">i</span><span class="pl-o">=</span><span class="pl-n">s</span><span class="pl-p">;</span><span class="pl-n">j</span><span class="pl-o">&gt;=</span><span class="pl-mi">0</span><span class="pl-p">;</span><span class="pl-n">i</span><span class="pl-o">--</span><span class="pl-p">){</span>
                <span class="pl-n">db</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">]</span><span class="pl-o">=</span><span class="pl-n">b</span><span class="pl-p">[</span><span class="pl-n">j</span><span class="pl-o">--</span><span class="pl-p">]</span><span class="pl-o">-</span><span class="pl-sc">&#39;0&#39;</span><span class="pl-p">;</span>
        <span class="pl-p">}</span>
        <span class="pl-k">for</span><span class="pl-p">(</span><span class="pl-kt">int</span> <span class="pl-n">i</span><span class="pl-o">=</span><span class="pl-n">s</span><span class="pl-p">;</span><span class="pl-n">i</span><span class="pl-o">&gt;=</span><span class="pl-mi">0</span><span class="pl-p">;</span><span class="pl-n">i</span><span class="pl-o">--</span><span class="pl-p">){</span>
                <span class="pl-n">dc</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">]</span><span class="pl-o">+=</span><span class="pl-n">da</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">]</span><span class="pl-o">-</span><span class="pl-n">db</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">];</span>
                <span class="pl-k">if</span><span class="pl-p">(</span><span class="pl-n">dc</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">]</span><span class="pl-o">&lt;</span><span class="pl-mi">0</span><span class="pl-p">){</span>
                        <span class="pl-n">dc</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-o">-</span><span class="pl-mi">1</span><span class="pl-p">]</span><span class="pl-o">--</span><span class="pl-p">;</span>
                        <span class="pl-n">dc</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">]</span><span class="pl-o">+=</span><span class="pl-mi">10</span><span class="pl-p">;</span>
                <span class="pl-p">}</span>
        <span class="pl-p">}</span>
        <span class="pl-k">if</span><span class="pl-p">(</span><span class="pl-n">fu</span><span class="pl-p">)</span><span class="pl-n">printf</span><span class="pl-p">(</span><span class="pl-s">&quot;-&quot;</span><span class="pl-p">);</span>
        <span class="pl-kt">bool</span> <span class="pl-n">zero</span><span class="pl-o">=</span><span class="pl-nb">true</span><span class="pl-p">;</span>
        <span class="pl-k">for</span><span class="pl-p">(</span><span class="pl-kt">int</span> <span class="pl-n">i</span><span class="pl-o">=</span><span class="pl-mi">0</span><span class="pl-p">;</span><span class="pl-n">i</span><span class="pl-o">&lt;</span><span class="pl-n">s</span><span class="pl-p">;</span><span class="pl-n">i</span><span class="pl-o">++</span><span class="pl-p">){</span>
                <span class="pl-k">if</span><span class="pl-p">(</span><span class="pl-n">dc</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">])</span><span class="pl-n">zero</span><span class="pl-o">=</span><span class="pl-nb">false</span><span class="pl-p">;</span>
                <span class="pl-k">if</span><span class="pl-p">(</span><span class="pl-n">dc</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">]</span> <span class="pl-o">||</span> <span class="pl-o">!</span><span class="pl-n">zero</span><span class="pl-p">)</span><span class="pl-n">printf</span><span class="pl-p">(</span><span class="pl-s">&quot;%d&quot;</span><span class="pl-p">,</span><span class="pl-n">dc</span><span class="pl-p">[</span><span class="pl-n">i</span><span class="pl-p">]);</span>
        <span class="pl-p">}</span>
        <span class="pl-k">if</span><span class="pl-p">(</span><span class="pl-n">zero</span><span class="pl-p">)</span><span class="pl-n">printf</span><span class="pl-p">(</span><span class="pl-s">&quot;0&quot;</span><span class="pl-p">);</span>
        <span class="pl-n">printf</span><span class="pl-p">(</span><span class="pl-s">&quot;</span><span class="pl-se">\n</span><span class="pl-s">&quot;</span><span class="pl-p">);</span>
        <span class="pl-k">return</span> <span class="pl-mi">0</span><span class="pl-p">;</span>
<span class="pl-p">}</span>
</cpde></pre></div>